1. Field of the Invention
The present invention relates to a method of adhering metal materials and especially to a method of adhering a metal protection cover and a metal shell for an optical transceiver module.
2. Background of the Invention
The computer industries have been widely applied in all fields and network technologies have been rapidly progressed. Therefore, people can easily access information and provides service by way of a network. Due to optoelectronic communication devices providing an enormous data transmission capacity, research is focused on optoelectronic technology for improving transmission quality. Recently, the optoelectronic industry combining the electronics industry and the optics industry has progressed to a high degree. An important device is an optical transceiver module which includes an optical transmitter, an optical receiver, or an optical transceiver combing both functions.
The transmitter is capable of transforming electronic signals into optical signals and transmitting the same to an optical fiber. Classifications are made in accordance with the light source; the light source of the transmitter of the optical fiber communication is mainly from a light emitting diode (LED) or a laser diode. Since the laser diode has the advantages of high output power, fast transmitting speed, small emission angle (i.e. a higher efficiency for coupling light source into an optical fiber), and a narrower frequency spectrum (smaller dispersion), the laser diode Is suitable for use in mid or long-range transmissions. While LED has the advantages of low cost and simpler utilization (simpler driving and compensation circuits), LED is only suitable for use in short-range transmissions. In particular, the laser diode, also called a semiconductor laser, has the advantages of small size, low power consumption, quick response, good collision resistance, long operation life, and high efficiency, so that the laser diode is very widely used in the application of optoelectronic products.
The main function of an optical receiver is to convert an optical signal to an electronic signal, of which the most critical component is a detector. The major principle of the detector is to generate enough energy by radiating light on a photo diode for exciting pairs of electrons and holes so as to generate a current signal.
Since optoelectronic components have very precise dimensions, equipment used to manufacture the same requires precise technology. The optical transceiver module therefore includes very precise dimensions. For example, the optical transceiver module manufacturing process starts with laser diode selection. Then, the laser diode is protected by TO-can process with a protection cover and gluing of the same to a metal shell, such as a T-housing made of stainless material. If the T-housing and the laser diode alignments are even a little bit biased, the optical transceiver module loses the optical signal strength and the communication quality is severely degraded. Therefore, the dimensions of the optical transceiver module are very important.
Conventionally, the protection cover is adhered to the metal shell with epoxy resin. For improving the adhesion strength thereof, a surface treatment such as sandblasting is usually performed on the metal shell. The epoxy resin easily absorbs water, especially when the optical transceiver module is exposed to high temperatures and high humidity. The absorbed water then degrades the adhesion strength thereof.
Therefore, there is a need to improve the adhesion strength and reliability of the protection cover and metal shell for the optical transceiver module so as to improve the quality thereof.